Audiologists typically rely on feedback from a hearing aid wearer to determine the quality of the audio signal being passed to the wearer's ear canal as well as to determine the effect of her adjustments and the appropriateness of the device for the patient. As the audiologist changes various fitting parameters, such as gain or compression thresholds, the audiologist will typically rely on the hearing aid wearer to provide feedback such as “that's better” or “that sounds worse,” etc. This customary approach can be particularly problematic when the hearing aid wearer is cognitively impaired or unable to express himself adequately for a variety of reasons including lack of experience with hearing instruments. Consequently, the audiologist typically has no first hand information to accurately determine the results of the adjustments that she is making to the hearing instrument.
One known method for monitoring hearing instrument performance is the use of a probe microphone, which may be inserted into the ear canal through the hearing aid vent. Probe microphones are typically used to verify hearing instrument parameters, such as real ear insertion gain (REIG). However, probe microphone methods are not widely used for a number of reasons, including the amount of effort involved, potential patient discomfort and risk, and the resultant changes to the acoustic field in the ear canal caused by insertion of the microphone.